I'm not an astronomer or astrophysicist, but this part makes no sense to me:

What does it matter how much light you can collect? The light rays from the galaxies traveled the exact same distance to get to earth--you couldn't possibly perceive a difference in the timescale observed just by, for example, using a larger aperture optical telescope.

I can see, for example, if you were able to gather more light you could have a more accurate representation of the objects (like seeing that they were more or less massive than previously expected), but you wouldn't be perceiving anything in terms of the timescale for the galaxies that you're observing. Unless there's something I'm missing?

edit--my assumption was that they're looking at the exact same galaxies that were observed with other telescopes, and that they're able to see "further" back in time. I think I understand now that they're observing not the same galaxies, but rather ones farther away--in which case, that makes sense now.

Light takes time to travel, 3x10^8 metres per second

Since those galaxies are so far away the light we are seeing is the light that was released from those galaxies approx 9 billion years ago hence why they say its like looking back in time. Its like taking a picture with an old camera, the type that burns UV/light onto film. Figuratively the light burned in on that picture remains from the time that it was taken, now think of the picture flying from that galaxy to ours at the speed of light. Once it gets here to earth we can see whats on the picture from that time.

If you already understood this somewhat then ignore and /hurr at the analogy

I'm not an astronomer or astrophysicist, but this part makes no sense to me:

What does it matter how much light you can collect? The light rays from the galaxies traveled the exact same distance to get to earth--you couldn't possibly perceive a difference in the timescale observed just by, for example, using a larger aperture optical telescope.

I can see, for example, if you were able to gather more light you could have a more accurate representation of the objects (like seeing that they were more or less massive than previously expected), but you wouldn't be perceiving anything in terms of the timescale for the galaxies that you're observing. Unless there's something I'm missing?

edit--my assumption was that they're looking at the exact same galaxies that were observed with other telescopes, and that they're able to see "further" back in time. I think I understand now that they're observing not the same galaxies, but rather ones farther away--in which case, that makes sense now.

It has to do with the amount of energy that can be collected by the main reflector and then subsequently absorbed by the CCD. At these distances, even a violently energetic event that outshines entire galaxies (Gamma ray bursts) fall victim to the inverse square law. So by the time that energy has crossed the billions of lightyears of space to reach earth, only something along the lines of .000000000000000000000001% of its initial energy remains. A snowflake hitting the ground would release more energy than that. So, to capture it, you need a very large telescope. The further away the objects you are looking at, the less energy you are recieving, and as a result you must have less interference and a larger device to snare what little remains.

Its the reason why a 6" reflector scope is only good for relatively nearby galaxies (under ~250M LY) whereas one several dozen feet across can grab light from across the universe.

Putting said scope in space cuts out the atmospheric interference, and allows you to penetrate further into the past. Switching to lower frequency wavelengths (infrared, microwave, and radio) allows you to dig a little bit further back due to redshift.

In short, having a bigger telescope is a pretty big deal when you may only capture a few thousand photons a night from your target object.

Since those galaxies are so far away the light we are seeing is the light that was released from those galaxies approx 9 billion years ago hence why they say its like looking back in time. Its like taking a picture with an old camera, the type that burns UV/light onto film. Figuratively the light burned in on that picture remains from the time that it was taken, now think of the picture flying from that galaxy to ours at the speed of light. Once it gets here to earth we can see whats on the picture from that time.

If you already understood this somewhat then ignore and /hurr at the analogy

Yeah, I knew that, but thanks for the response--I didn't grasp that the telescope used in the new study is so vastly superior in sensitivity to the ones used previously (since this sort of research has been going on for such a long time, I just figured that there were really no gains to be maid in the actual telescope portion).

Quote:

Originally Posted by Cyrious

It has to do with the amount of energy that can be collected by the main reflector and then subsequently absorbed by the CCD. At these distances, even a violently energetic event that outshines entire galaxies (Gamma ray bursts) fall victim to the inverse square law. So by the time that energy has crossed the billions of lightyears of space to reach earth, only something along the lines of .000000000000000000000001% of its initial energy remains. A snowflake hitting the ground would release more energy than that. So, to capture it, you need a very large telescope. The further away the objects you are looking at, the less energy you are recieving, and as a result you must have less interference and a larger device to snare what little remains.

Its the reason why a 6" reflector scope is only good for relatively nearby galaxies (under ~250M LY) whereas one several dozen feet across can grab light from across the universe.

In short, having a bigger telescope is a pretty big deal when you may only capture a few thousand photons a night from your target object.

Yeah, I get that--just didn't understand initially that the first telescopes used for these studies were so poor in comparison to the one being discussed in the article.

Quote:

Originally Posted by Cyrious

Putting said scope in space cuts out the atmospheric interference, and allows you to penetrate further into the past.

This is a terrestrial telescope.

Quote:

Originally Posted by Cyrious

Switching to lower frequency wavelengths (infrared, microwave, and radio) allows you to dig a little bit further back due to redshift.

Wait, now you've really lost me. They're using mirrors and optics--what do microwaves and radio waves have anything to do with it? I thought they were gathering actual optical "visible" light (okay, let's say from the UV to the IR) to make these studies? Mirrors and optics don't work for radio or microwaves.

Also, why would red-shifted light have any effect on their measurements? Or do you just mean "redshift" as in, moving to higher wavelength (lower frequency)? I am not sure if you're referring to the actual doppler effect, or just using the term as a comparison. Regardless, I don't see how this could matter since they're using an optical telescope. Sure, there might be other auxiliary detectors (such as radio and whatnot), but the measurements are based on optical observations.

Wait, now you've really lost me. They're using mirrors and optics--what do microwaves and radio waves have anything to do with it? I thought they were gathering actual optical "visible" light (okay, let's say from the UV to the IR) to make these studies? Mirrors and optics don't work for radio or microwaves.

Also, why would red-shifted light have any effect on their measurements? Or do you just mean "redshift" as in, moving to higher wavelength (lower frequency)? I am not sure if you're referring to the actual doppler effect, or just using the term as a comparison. Regardless, I don't see how this could matter since they're using an optical telescope. Sure, there might be other auxiliary detectors (such as radio and whatnot), but the measurements are based on optical observations.

We have tools to detect light further down the spectrum than our eyes can detect, and that extends into optics/mirrors (it's still light). We can see red-shifted light farther away. That simple.

We have tools to detect light further down the spectrum than our eyes can detect, and that extends into optics/mirrors (it's still light). We can see red-shifted light farther away. That simple.

It's an optical telescope using optical lenses and optical mirrors--I work with optics every day, trust me when I say that optical mirrors and lenses don't work on radio waves or microwaves (for those, you'd need to use radio telescopes). You're very lucky if your visible optics might respond to UV or IR light. At best, if they're interested in detecting the lesser-perturbed longer-wavelength (red-shifted) light through the atmosphere, they can optimize their optics for collecting IR light--but then you run into the big problem where camera/detector sensitivity takes a huge dive in the near IR/IR--like 40% max QE as opposed to nearly 80% for the visible. Even super-cooled IR detectors can't match the sensitivity or QE of visible detectors.

I still don't understand what radio waves or microwaves has to do with this optical telescope.